/* mpi-inline.h  -  Internal to the Multi Precision Integers */

#ifndef G10_MPI_INLINE_H
#define G10_MPI_INLINE_H

#ifndef G10_MPI_INLINE_DECL
#define G10_MPI_INLINE_DECL static inline
#endif

G10_MPI_INLINE_DECL mpi_limb_t mpihelp_add_1(mpi_ptr_t  res_ptr,
                                             mpi_ptr_t  s1_ptr,
                                             mpi_size_t s1_size,
                                             mpi_limb_t s2_limb)
{
    mpi_limb_t x;

    x = *s1_ptr++;
    s2_limb += x;
    *res_ptr++ = s2_limb;
    if (s2_limb < x) { /* sum is less than the left operand:
                          handle carry */
        while (--s1_size) {
            x          = *s1_ptr++ + 1; /* add carry */
            *res_ptr++ = x;             /* and store */
            if (x)                      /* not 0 (no overflow): we can stop */
                goto leave;
        }
        return 1; /* return carry (size of s1 to small) */
    }

leave:
    if (res_ptr != s1_ptr) { /* not the same variable */
        mpi_size_t i;        /* copy the rest */
        for (i = 0; i < s1_size - 1; i++) res_ptr[i] = s1_ptr[i];
    }
    return 0; /* no carry */
}

G10_MPI_INLINE_DECL mpi_limb_t mpihelp_add(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
                                           mpi_size_t s1_size, mpi_ptr_t s2_ptr,
                                           mpi_size_t s2_size)
{
    mpi_limb_t cy = 0;

    if (s2_size) cy = mpihelp_add_n(res_ptr, s1_ptr, s2_ptr, s2_size);

    if (s1_size - s2_size)
        cy = mpihelp_add_1(res_ptr + s2_size, s1_ptr + s2_size,
                           s1_size - s2_size, cy);
    return cy;
}

G10_MPI_INLINE_DECL mpi_limb_t mpihelp_sub_1(mpi_ptr_t  res_ptr,
                                             mpi_ptr_t  s1_ptr,
                                             mpi_size_t s1_size,
                                             mpi_limb_t s2_limb)
{
    mpi_limb_t x;

    x          = *s1_ptr++;
    s2_limb    = x - s2_limb;
    *res_ptr++ = s2_limb;
    if (s2_limb > x) {
        while (--s1_size) {
            x          = *s1_ptr++;
            *res_ptr++ = x - 1;
            if (x) goto leave;
        }
        return 1;
    }

leave:
    if (res_ptr != s1_ptr) {
        mpi_size_t i;
        for (i = 0; i < s1_size - 1; i++) res_ptr[i] = s1_ptr[i];
    }
    return 0;
}

G10_MPI_INLINE_DECL mpi_limb_t mpihelp_sub(mpi_ptr_t res_ptr, mpi_ptr_t s1_ptr,
                                           mpi_size_t s1_size, mpi_ptr_t s2_ptr,
                                           mpi_size_t s2_size)
{
    mpi_limb_t cy = 0;

    if (s2_size) cy = mpihelp_sub_n(res_ptr, s1_ptr, s2_ptr, s2_size);

    if (s1_size - s2_size)
        cy = mpihelp_sub_1(res_ptr + s2_size, s1_ptr + s2_size,
                           s1_size - s2_size, cy);
    return cy;
}

#endif /*G10_MPI_INLINE_H */
